The purpose of this study was to investigate the status of mentoring and induction programs and their impacts on beginning music teachers. I measured mentoring program comprehensiveness, along with mentor functions and attributes, mentor support practices, and mentor effectiveness as perceived by mentees. I also explored the effects of mentee status, perceived mentor effectiveness, and mentor content area on reflective practice, teaching efficacy, and professional commitment. Data were collected from beginning music teachers within 10 states in Fall 2016 (N = 245) and again in March 2017 (n = 154). After using exploratory and confirmatory factor analysis techniques to reduce multi-item variables into smaller, latent factor structures, I utilized multivariate inferential statistics to explore whether beginning music teachers’ growth in reflective practice, teaching efficacy, and professional commitment over time was connected to mentor content area or mentor effectiveness (as perceived by the mentee). Then, I used path analysis techniques to explore relations among mentor and mentee characteristics, beginning teacher perceptions of mentor functions and effectiveness, and beginning music teachers’ self-reports of reflective practice, teaching efficacy, and professional commitment. Reflective practice, teaching efficacy, and professional commitment did not differ by mentee status (current, former). Additionally, perceived mentor effectiveness (as moderated by mentor content area) did not impact reflective practice, teaching efficacy, or professional commitment over time. In fact, mentees with non-music mentors reported increases in reflective practice, teaching efficacy, and professional commitment, but these gains were not statistically different from mentee respondents who were assigned a music mentor. Lastly, a measurement model that predicts professional commitment—including direct effects of Reflection-on-Action, Reflection-in-Action, and Classroom Management and Engagement efficacy, and indirect effects of Reflection-in-Action and mentee status—is proposed. Only mentee status predicted Classroom Management and Engagement efficacy; current mentees tended to be less efficacious. None of the other demographic or mentoring program variables—including mentor effectiveness, mentor content area, level of education, school setting, and years of teaching experience—predicted reflective practice, teaching efficacy, or professional commitment. Implications for beginning music teacher mentoring and recommendations for future research are discussed.</p